I'm installing a new hard drive and I already have it but its hanging by rubber bands. I bought this computer originally prebuilt so it didn't come with extra rails. I've googled over and over and can't find anyone selling these damned mounting rails. About a month ago I emailed NZXT and I still have no response. Anyone know where I can find these bastards?
If it helps at all they look like this:

Have you thought about modifying the case to fit it? It's not like hard drives need a special mounting system, just something to keep them from rattling around too much. I don't know what to suggest as I can't see on the inside of your case.

A while back my brother lost his mounting brackets and so when he wanted to add a hard drive, we just took some foam tape and stuck it to the bottom of the case. It works fine and actually worked better for cable management than the mounted option. People do it all the time with SSDs just because they're so small and create no vibration.